Table 1.
Characteristics of study populations by site
| Characteristic | Season time point | The Gambia | Kenya | P |
|---|---|---|---|---|
| Number | 603 | 245 | — | |
| Median age, mo (IQR) | 46.8 (35.6, 59.4) | 48.7 (25.7, 67.8) | .78 | |
| Median BMI (IQR) | 14.5 (13.8, 15.4) | 15.3 (14.5, 16.2) | <.0005 | |
| Male gender, no. | 318 (52.7%) | 136 (55.5%) | .47 | |
| Minority ethnic group,* no. | 61 (10.1%) | 38 (15.5%) | — | |
| HbAS, no. | 78 (13.4%) | 29 (11.8%) | .54 | |
| G6PDd A- type, no.† | 23 (4.9%) | 72 (34.4%) | <.0005 | |
| Hepcidin, ng/mL | Start | 11.2 (9.9, 12.7) | 3.8 (3.1, 4.7) | <.0005 |
| End | 4.2 (3.6, 4.8)‡ | 1.3 (1.0, 1.7)‡ | <.0005 | |
| ACT, g/L or CRP, mg/L | Start | 0.45 (0.44, 0.46) | 0.78 (0.64, 0.95) | — |
| End | 0.39 (0.39, 0.40)‡ | 0.87 (0.73, 1.05) | — | |
| Ferritin, µg/L | Start | 25.5 (23.7, 27.4) | 18.4 (16.2, 20.9) | <.0005 |
| End | 21.1 (19.5, 22.8)‡ | 13.6 (12.3, 15.2)‡ | <.0005 | |
| sTfR, mg/L | Start | 3.4 (3.3, 3.5) | 3.7 (3.5, 3.9) | .002 |
| End | 4.1 (4.0, 4.3)‡ | 3.6 (3.4, 3.8) | <.0005 | |
| Hb concentration, g/dL | Start | 10.6 (10.5, 10.7) | n/a | — |
| End | 9.9 (9.8, 10.1)‡ | 10.3 (10.0, 10.6) | .13 | |
| MCV, fL | Start | 75.4 (74.6, 76.2) | n/a | — |
| End | 74.7 (73.9, 75.5)‡ | 71.6 (69.8, 73.5) | <.0005 | |
| ID, no. (%) | Start | 112/601 (18.6%) | 91/238 (38.2%) | <.0005 |
| End | 176/597 (29.5%)‡ | 114/245 (46.5%)§ | <.0005 | |
| IDA, no. (%) | Start | 83/595 (14.0%) | n/a | — |
| End | 150/595 (25.2%)‡ | 45/82 (54.9%) | <.0005 | |
| P. falciparum parasitemia, no. (%) | Start | 62/601 (10.3%) | 41/243 (16.9%) | .04 |
| End | 156/602 (25.9%)‡ | 20/242 (8.3%)‡ | <.0005 |
All subjects had hepcidin measurements at 2 time points with no missing data. Other measurements may have been missing data from one or other time point. Only 82 Kenyan children had complete blood count data. Geometric mean values are presented for continuous variables, and categorical variables are represented by proportions (%). All analyses, except for that of age, were adjusted for age. ID was defined as ferritin <12 µg/L or ferritin <30 µg/L with inflammation (ACT >0.6 g/L or CRP >10 mg/L). IDA was defined as ID with Hb <11 g/dL if aged 6 mo to 4 y or Hb <11.5 g/dL if aged 5-12 y.
n/a, not available.
Ethnic groups in the Gambia were Mandinka and Fulani (minority group) and in Kenya were Giriama and Chonyi (minority group).
G6PDd A- heterozygotes and homozygotes combined.
P < .0005 for difference between start and end of season.
P = .007 for difference between start and end of season.